1. Technical Field
The present disclosure is related to in vivo medical devices, and more particularly to inflatable devices for use in bodily vessels or lumens, for example vasculature such as arteries.
2. Description of the Related Art
Numerous medical procedures now employ catheters to enter bodily vessels, for example vasculature such as arteries, veins, and or the heart. Such procedures are often percutaneous, providing numerous advantages over more traditional surgery, for example reduced trauma and faster healing. However, catheter procedures are often difficult to perform. Catheter procedures require a care provider (e.g., medical doctor or physician) to guide a catheter or guide wire through the vasculature to a desired position without direct visual feedback. The care provider may receive tactile feedback and/or secondary visual feedback. The secondary visual feedback may come from a camera mounted to the catheter or guide wire. The secondary visual feedback may alternatively come from detection of the catheter or guide wire using medical imaging systems for example ultrasound, computer tomography (CT), real-time magnetic resonance (MR), X-ray, fluoroscopy and/or other radiological apparatus and methods. In either case, the care provider does not have direct visual contact with the catheter or guide wire.
A variety of procedures referred to as angioplasty, widen vasculature and/or remove blockages from vasculature using an inflatable structure such as a balloon positioned at a distal end of a catheter. Often the procedure will include implantation of a structure such as a stent in vasculature to support the vasculature. While some stents are self-expanding, other stents are expanded to contact the wall of the vasculature using a balloon.
The catheter typically includes at least one inflation lumen which allows the balloon to be inflated and deflated and a guide wire lumen allowing the catheter to be guided in the bodily vessel. Balloons are typically made of flexible but inelastic materials, which do not appreciably stretch even when subjected to the high pressures (e.g., 10-30 ATM) commonly employed to inflate such balloons). Hence, the balloon is often folded when in an uninflated state or configuration to provide a relatively small cross sectional diameter. This allows the balloon to fit in the vasculature and/or to fit in the catheter. Rather than stretching, the balloon unfolds in response to inflation, to provide a relatively large cross sectional diameter when in an inflated state or configuration. This allows the balloon to physically engage the walls of the vasculature and/or expand the stent to physically engage the walls of the vasculature.
Typically, catheters must travel a tortuous path through the vasculature. Flexible catheters and/or guide wires have been developed to facilitate such travel. Flexible stents are also now available, which facilitate travel through the vasculature. However, the flexibility of such stents tends to be limited by the flexibility of the inflation balloon. Consequently, numerous short stents may be employed to provide support to an appreciable length of the vasculature. Each stent requires a respective balloon which increases the complexity of the catheter procedure, which as previously noted is a difficult procedure to perform. Using multiple short stents also leads to discontinuities of vasculature.
Improvements in devices and methods associated with catheter based medical procedures are highly desirable.